We actually just migrated off yesterday... we went with an independent vendor like Aiven instead of the clouds because they move too slowly and don't have enough features.
For Gcloud and especially in Europe, I think these two are the only options that I’m aware of (at least for PG and redis)
Minor: less downtime for maintenance, point-in-time restore
The rest is summed up here: https://news.ycombinator.com/item?id=16872723